Justin and Ariana gave the duet of a lifetime when they sang ‘Love Me Harder’ together during Ari’s March 28 Miami concert. In fact, Justin was so wrapped up in the moment that he totally forgot her lyrics — oops! Watch his flub — and apology — here!

Justin Bieber, 21, gave Arianators and Beliebers a huge surprise when he stepped out to duet with Ariana Grande, 21, during her Miami concert on March 28. While singing an unforgettable, sexy rendition of “Love Me Harder,” Justin accidentally messed up the lyrics and was forced to make up his own!

After he began improvising, Ariana picked up on his mistake and jumped in to help him out. Phew! At least Justin didn’t go off key and was able to hold the tune. Besides his tiny mistake, they were absolutely flawless together!

However, it seemed like Justin was beating himself up for forgetting the lyrics and apologized to fans. (Hear his apology at 4:12.)

“So I’m feeling a little bad. I forgot the words, Ariana,” Justin says. “I’ve been trying to memorize them backstage for like an hour, I feel so bad I’m so sorry. Do you guys forgive me for forgetting the words? I feel terrible. “

Aw, poor Justin! It seems like he really felt bad for his little slip. We forgive you Justin! Plus, Ariana didn’t seem to mind his mistake.

Regardless of forgetting Ariana’s lyrics, Justin totally made it up to fans by singing his hits “All That Matters” and “As Long As You Love Me” with Ariana!

Justin’s surprise hit home with a ton of fans, and we are obsessed with Justin and Ariana’s musical chemistry! Both of their angelic voices are amazing together and mesh so well. Can we expect a future collaboration? We can only hope!

What do YOU think, HollywoodLifers? Do you think it’s a big deal that Justin forgot Ariana’s lyrics? Tell us how you feel below!